The sum of their momentums is still the same with the sum of their momentums before they have collided with each other. There can be slight differences with their momentum depending on the sizes of the objects that will collide with each other. The speed of the objects will be a factor. The other factor has to be the size of the objects that will hit each other.
When a large object collides with a smaller object, expect that the larger object will have a higher momentum as compared to the smaller object. An object with a higher speed may be stopped when it hits a bigger object or the effect of the collision will be more felt by the object with higher speed.